1. Field of the Invention
The present invention relates to a printing system having a plurality of computers and printer, which are connected with each other via a communication network.
2. Description of the Related Art
In a printing system having a plurality of computers and a printer, the computers are connected with the printer via a local network. The computer user creates a document and/or an image by using the computer. The computer generates document data and/or image data corresponding to the document and/or the image, and sends them to the printer via the local network. The printer receives the document data and/or the image data, and then converts these data to print data (e.g., bitmap data), and then prints the print data onto a printing medium such as printing paper.
Such a printing system has a preview function. If the computer user wishes to confirm the content of the document and/or the image to be actually printed by the printer before printing, the computer user can view a preview image corresponding to the document and/or the image with a display device of the computer such as a CRT display. To accomplish the preview function, the printer generates the preview image data and sends it to the computer via the local network. The computer receives the preview image data, and display the preview image corresponding to the received preview image data.
Such a printing system using the local network has a disadvantage that velocity of the communication becomes slow when a large number of computers simultaneously communicate with the printer. Image data such as preview image data generally has a large size. Therefore, if the local network is crowded, it takes a long time to send preview image data from the printer to the computer via the local network. If the resolution of the preview image is reduced, the size of the preview image data is also reduced. Therefore, it is possible to reduce the length of time required to send the preview image data from the printer to the computer. However, if the resolution of the preview image is reduced, the computer user cannot confirm the detail of the image.
In recent years, an internet-becomes widespread. Document data and image data can be sent from one computer to another computer via the internet. Further, document data :and image data can be directly sent from one computer to a printer via the internet However, if communication lines of the internet are crowded, velocity of the communication on the internet becomes slow. In this case, it takes a long time to send document data and image data via the internet. Especially, the size of image data is relatively large. Therefore if communication lines of the internet are crowded, the length of time necessary for sending the image data becomes extremely long.
Further, in the printing system wherein a single printer is shared with a plurality of computers, the printer manages a plurality of print jobs, and the printer carries out a printing process for each print job. In such a printer, when the communication lines of the internet are crowded, if the printer executes a print job which requests that the printer directly receives image data from a computer via the internet and directly prints images corresponding to image data, it takes a long time for the printer to finish this job. Therefore, execution of another print job are delayed.
It is therefore a first object of the present invention to provide a printing system which can send data to form a preview image from a printing apparatus to a data processing apparatus via a network in a short time.
It is a second object of the present invention to provide a printing system which can change resolution of a preview image.
The above mentioned first object can be achieved by a printing system of the present invention. The printing system of the present invention has at least one data processing apparatus for generating data to form an image and a printing apparatus for printing the image. The data processing apparatus and the printing apparatus are connected with each other via a network. The data processing apparatus has: a generating device for generating print command data, which includes a plurality of commands to form the image to be printed; a print command data sending device for sending the generated print command data to the printing apparatus; a dot data receiving device for receiving dot data from the printing apparatus; a preview image forming device for forming a preview image by using the received dot data; and a displaying device for displaying the preview image. The printing apparatus has: a print command data receiving device for receiving the print command data from the data processing apparatus; a converting device for converting the received print command data into print data, which includes a plurality of the dot data each of which corresponds to a different dot of the image to be printed; a first extracting device for extracting a first part of the dot data included in the print data; and a dot data sending device for sending the extracted dot data to the data processing apparatus via the network.
In the data processing apparatus, the generating device generates print command data. The print command data includes a plurality of commands to form an image to be printed. Next, the print command sending device sends the print command data to the printing apparatus.
Next, in the printing apparatus, the print command data receiving device receives the print command data from the data processing apparatus. Next, the converting device converts the received print command data into print data. The print data includes a plurality of dot data each of which corresponds to a different dot of the image to be printed. Next, the first extracting device extracts a first part of the dot data included in the print data. That is, the first extracting device extracts the dot data corresponding to specified dots of the image to be printed. Next, the dot data sending device sends the extracted dot data, i.e., the first part of the dot data to the data processing apparatus via the network. As the total amount of the first part of the dot data is smaller than the total amount of all of the dot data included in the print data, the dot data sending device can send the first part of the dot data in a short time, as compared with sending all of the dot data included in the print data.
Next, in the data processing apparatus, the dot data receiving device receives the dot data from the printing apparatus. Next, the preview image forming device forms a preview image by using the received dot data. Next, the displaying device displays the preview image. The preview image shows the image to be printed. The user can confirm the content and the condition of the image by viewing the preview image.
When the first extracting device extracts the first part of the dot data from the print data, the first extracting device may divide the print data into a plurality of groups, each of which has a predetermined amount of the dot data, and extract a part of the dot data included in each group. This means that the first extracting device may divide the image into a plurality of areas, each of which has a predetermined number of dots, and extracts the dot data corresponding to a part of dots existing in the area. By using the dot data extracted in this manner, the preview image forming device can form a preview image which represents the image to be printed in low resolution.
The above mentioned second object can be achieved by a printing system of the present invention. Like the aforementioned printing system, this printing system has a data processing apparatus and a printing apparatus. The data processing apparatus includes the same devices as the aforementioned data processing apparatus, and further includes a request command sending device for sending a request command to the printing apparatus. The printing apparatus includes the same devices as the aforementioned printing apparatus, and further includes: a request command receiving device for receiving the request command from the data processing apparatus; and a second extracting device for extracting a second part of the dot data included in the print data in response to the received request command.
As mentioned above, in the data processing apparatus, the preview image is formed by using the first part of the dot data. After this preview image is formed, the request command sending device of the data processing apparatus sends a request command to the printing apparatus.
Next, in the printing apparatus, the request command receiving device receives the request command from the data processing apparatus. In response to the reception of the request command, the second extracting device extracts a second part of the dot data included in the print data. The aforementioned first extracting device extracts the first part of the dot data from the print data, while the second extracting device extracts the second part of the dot data from the same print data. The second part is different from the first part. Namely, the second extracting device extracts dot data corresponding to dots which is different from dots corresponding to dot data extracted by the first extracting device. Next, the extracted second part of the dot data is sent from the printing apparatus to the data processing apparatus.
Next, in the data processing apparatus, the second part of the dot data is received. Next, a preview image is formed by using the first part of the dot data, which has been previously received, and the second part of the dot data, which has been now received, and it is displayed. As the preview image is formed by using the first part of the dot data and the second part of the dot data, resolution of the preview image can be increased. Further, by using the first part of the dot data and the second part of the dot data, the magnification of the preview image can be formed.
Thus, by viewing the preview image formed by only using the first part of the dot data, the user can confirm the outline of the image to be printed. Further, by viewing the preview image formed by using both the first part of the dot data and the second part of the dot data, the user can confirm the detail of the image to be printed.
The above mentioned first object can be also achieved by a printing system of the present invention. The printing system of the present invention has at least one data processing apparatus and a printing apparatus, which are connected with each other via a network. Like the aforementioned data processing apparatus, this data processing apparatus also has: a generating device; a print command data sending device; a dot data receiving device; a preview image forming device; and a displaying device. This data processing apparatus further has: a measuring device for measuring velocity of a reception of the dot data from the printing apparatus; and a request command sending device for sending a request command to the printing apparatus if the measured velocity is slower than a predetermined velocity. Like the aforementioned printing apparatus, this printing apparatus also has: a print command data receiving device; a converting device; a first extracting device; and a dot data sending device. This printing apparatus further has: a request command receiving device for receiving the request command from the data processing apparatus; and a second extracting device for extracting a second part of the dot data included in the print data in response to the received request command.
When the data processing process receives the first part of the dot data from the printing apparatus, the measuring device measures velocity of the reception of the first part of the dot data. If the velocity of the reception is slower than a predetermined velocity due to, for example, congestion of the network, the data processing apparatus sends a request command to the printing apparatus. In response to this request command, the printing apparatus extracts a second part of the dot data included in the print data, and sends the extracted second part of the dot data to the data processing apparatus via the network. The data processing apparatus receives the second part of the dot data, and forms the preview image by using the second part of the dot data, and displays the formed preview image on the display device of the data processing apparatus. If the amount of the second part of the dot data is smaller than the amount of the first part of the dot data, the velocity of the reception of the second part of the dot data is faster than the velocity of the reception of the first part of the dot data. Thus, it is possible to send the dot data from the printing apparatus to the data processing apparatus via the network in a short time.
The above mentioned first object can be also achieved by a preview image displaying method of the present invention. The preview image displaying method is used for a printing system having at least one data processing apparatus for generating data to form an image and a printing apparatus for printing the image. The data processing apparatus and the printing apparatus are connected with each other via a network. The preview image displaying method has the processes of: sending the print command data from the data processing apparatus to the printing apparatus; converting the print command data into print data in the printing apparatus; extracting a first part of the dot data from the print data in the printing apparatus; sending the extracted first part of dot data from the printing apparatus to the data processing apparatus via the network; receiving the first part of the dot data from the printing apparatus in the data processing apparatus; forming a preview image by using the received first part of dot data in the data processing apparatus; and displaying the preview image on a display device of the data processing apparatus.
Thus, the first part of the dot data is extracted from the print data, and sent from the printing apparatus to the data processing apparatus via the network. Then, the preview image is formed by using the first part of the dot data. As the total amount of the first part of the dot data is smaller than the total amount of all of the dot data included in the print data, it is possible to send the first part of the dot data from the printing apparatus to the data processing apparatus via the network in a short time, as compared with sending all of the dot data included in the print data.
The above mentioned second object can be also achieved by a preview image displaying method of the present invention. This preview image method includes the same processes as the aforementioned preview image displaying method, and further includes: sending a request command from the data processing apparatus to the printing apparatus, after the preview image is displayed; extracting a second part of the dot data from the print data in the printing apparatus, in response to the received request command; sending the extracted second part of the dot data from the printing apparatus to the data processing apparatus via the network; reforming the preview image by using the first part of the dot data and the second part of the dot data in the data processing apparatus; and displaying the reformed preview image on the display device of the data processing apparatus.
As the preview image is reformed by using the first part of the dot data and the second part of the dot data, resolution of the preview image can be increased. Further, by using the first part of the dot data and the second part of the dot data, the magnification of the preview image can be formed.
Thus, by viewing the preview image formed by only using the first part of the dot data, the user can first confirm the outline of the image to be printed. By viewing the preview image formed by using both the first part of the dot data and the second part of the dot data, the user can next confirm the detail of the image to be printed.
The above mentioned first object can be also achieved by a preview image displaying method of the present invention. This preview image displaying method has the processes of: sending the print command data from the data processing apparatus to the printing apparatus; converting the print command data into print data in the printing apparatus; extracting a first part of the dot data from the print data in the printing apparatus; sending the extracted first part of dot data from the printing apparatus to the data processing apparatus via the network; receiving the first part of the dot data from the printing apparatus; forming a preview image by using the first part of dot data received from the printing apparatus in the data processing apparatus; and displaying the preview image on a display device of the data processing apparatus. This method further has the processes of: measuring velocity of a reception of the first part of the dot data from the printing apparatus in the data processing apparatus when the first part of the dot data is received; sending a request: command from the data processing apparatus to the printing apparatus if the measured velocity is slower than a predetermined velocity; extracting a second part of the dot data included in the print data in the printing apparatus, in response to the received request command; sending the extracted second part of the dot data from the printing apparatus to the data processing apparatus via the network; forming the preview image by using the second part of the dot data in the data processing apparatus; and displaying the preview image formed by using the second part of the dot data on the display device of the data processing apparatus.
In case that the amount of the second part of the dot data is smaller than the amount of the first part of the dot data, the velocity of the reception of the second part of the dot data is faster than the velocity of the reception of the first part of the dot data. Thus, it is possible to send the dot data from the printing apparatus to the data processing apparatus via the network in a short time.
The nature, utility, and further feature of this invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with the accompanying drawings briefly described below.